Liquid crystal display device and method of manufacturing the same

ABSTRACT

Provided are liquid crystal display and the method for manufacturing the same. According to an aspect of the present disclosure, there is provided a liquid crystal display device, including: a first substrate; a gate electrode disposed on the first substrate; a semiconductor pattern layer disposed on the gate electrode; and a source electrode and a drain electrode disposed on the semiconductor pattern layer and facing each other, wherein the gate electrode includes a reference plane and a protrusion protruding from the reference plane in a horizontal direction, and the protrusion overlaps the source electrode and the drain electrode.

This application claims priority from Korean Patent Application No.10-2015-0126808 filed on Sep. 8, 2015 in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND

1. Field of the Disclosure

The present disclosure relates to a liquid crystal display device and amethod of manufacturing the same.

2. Description of the Related Art

The importance of a display device has increased with the development ofmultimedia. Accordingly, various types of liquid crystal devices, suchas a liquid crystal display (LCD) device, an organic light emittingdisplay (OLED) device, and the like, have been used.

Among these, a liquid crystal display device, which is one of the mostwidely used flat panel display devices, includes two substrates providedwith field generating electrodes, such as a pixel electrode and a commonelectrode, and a liquid crystal layer disposed between the twosubstrates. The liquid crystal display device is configured such thatwhen a voltage is applied to the field generating electrodes to generatean electric field in the liquid crystal layer, the direction of liquidcrystal molecules in the liquid crystal layer is determined, therebycontrolling the polarization of incident light to display an image.

Generally, the liquid crystal display device requires a large-sizedsubstrate, such as a glass substrate, and a thin film transistor (TFT)having excellent performance.

SUMMARY

Aspects of the present disclosure provide a liquid crystal displaydevice that prevents the characteristics of a semiconductor patternlayer from being deteriorated by the light provided from a backlightunit.

Aspects of the present disclosure also provide a method of manufacturinga liquid crystal display device that prevents the characteristics of asemiconductor pattern layer from being deteriorated by the lightprovided from a backlight unit.

According to an aspect of the present disclosure, there is provided aliquid crystal display device, including: a first substrate; a gateelectrode disposed on the first substrate; a semiconductor pattern layerdisposed on the gate electrode; and a source electrode and a drainelectrode disposed on the semiconductor pattern layer and facing eachother, wherein the gate electrode includes a reference plane and aprotrusion protruding from the reference plane in a horizontaldirection, and the protrusion overlaps the source electrode and thedrain electrode.

The gate electrode may include a first sub gate electrode and a secondsub gate electrode disposed on the first sub gate electrode, the firstsub gate electrode may include an overlapping area in which the firstsub gate electrode overlaps the second sub gate electrode, andnon-overlapping areas in which the first sub gate electrode does notoverlap the second sub gate electrode, and the protrusion may includethe non-overlapping areas.

The first sub gate electrode and the second sub gate electrode may bemade of materials different from each other.

The gate electrode may include: a first sub gate electrode; a second subgate electrode disposed on the first sub gate electrode; and a third subgate electrode disposed on the second sub gate electrode, wherein thefirst sub gate electrode and the second sub gate electrode include anoverlapping area in which the first sub gate electrode and the secondsub gate electrode overlap the third sub gate electrode, andnon-overlapping areas in which the first sub gate electrode and thesecond sub gate electrode do not overlap the third sub gate electrode,and the protrusion includes the non-overlapping areas of the first subgate electrode and the second sub gate electrode.

The third sub gate electrode and the second sub gate electrode may bemade of materials different from each other.

The third sub gate electrode and the first sub gate electrode may bemade of materials the same as each other.

The width of the protrusion may be equal to the width of the sourceelectrode or the drain electrode overlapping the protrusion.

The source electrode may include a bar-shaped portion and a U-shapedportion, and the protrusion may overlap the bar-shaped portion of thesource electrode.

A plurality of protrusions may be disposed to correspond to the sourceelectrode and the drain electrode.

The source electrode may include first to third source electrodes, thedrain electrode may include first to third drain electrodescorresponding to the first to third source electrodes, and theprotrusion may include first to fifth protrusions, wherein the first tofifth protrusions may respectively overlap the first to third sourceelectrodes and the first to third drain electrodes.

The liquid crystal display device may further include: a secondsubstrate facing the first substrate; and a common electrode disposed onthe second substrate.

According to another aspect of the present disclosure, there is provideda method of manufacturing a liquid crystal display device, including:providing a first substrate including a first conductive film and asecond conductive film disposed on the first conductive film; forming afirst photoresist pattern on the second conductive film; and forming agate electrode including a first sub gate electrode and a second subgate electrode by etching the first conductive film and the secondconductive film using the first photoresist pattern as an etching mask,wherein the gate electrode includes a reference plane and a protrusionprotruding from the reference plane in a horizontal direction.

The first conductive film and the second conductive film may be made ofmaterials having etch rates different from each other with respect to apredetermined etchant.

The forming the gate electrode including the first sub gate electrodeand the second sub gate electrode by etching the first conductive filmand the second conductive film using the first photoresist pattern as anetching mask may include: wet-etching the first conductive film and thesecond conductive film.

The forming the gate electrode including the first sub gate electrodeand the second sub gate electrode by etching the first conductive filmand the second conductive film using the first photoresist pattern as anetching mask may include: over-etching the second sub gate electrode toform the protrusion as a part of the first sub gate electrode afterforming the first sub gate electrode and the second sub gate electrodeby etching the first conductive film and the second conductive film.

However, aspects of the present disclosure are not restricted to the oneset forth herein. The above and other aspects of the present disclosurewill become more apparent to one of ordinary skill in the art to whichthe present disclosure pertains by referencing the detailed descriptiongiven below.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of the present disclosure willbecome more apparent when the exemplary embodiments described herein areconsidered with reference to the attached drawings, in which:

FIG. 1 is a plan view of a liquid crystal display device according to anembodiment of the present disclosure;

FIG. 2 is a plan view showing only a part of the configuration of FIG.1;

FIG. 3 is a cross-sectional view taken along the line I-I′ of FIG. 1;

FIG. 4 is a cross-sectional view of a liquid crystal display deviceaccording to another embodiment of the present disclosure;

FIG. 5 is a plan view of a liquid crystal display device according toanother embodiment of the present disclosure;

FIG. 6 is a plan view of a liquid crystal display device according tostill another embodiment of the present disclosure;

FIG. 7 is a plan view showing only a part of the configuration of FIG.6;

FIG. 8 is a cross-sectional view of a liquid crystal display deviceaccording to still another embodiment of the present disclosure;

FIG. 9 is a cross-sectional view of a liquid crystal display deviceaccording to still another embodiment of the present disclosure; and

FIGS. 10, 11, 12, 13, 14 and 15 are cross-sectional views illustrating amethod of manufacturing a liquid crystal display device according to anembodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The aspects and features of the present disclosure and methods forachieving the aspects and features will be apparent by referring to theembodiments described in detail with reference to the accompanyingdrawings. However, the present disclosure is not limited to theembodiments disclosed hereinafter but may be implemented in diverseforms. The matters defined in the description, such as the detailedconstruction and elements, are provided to assist those of ordinaryskill in the art in a comprehensive understanding of the disclosure andare non-limiting.

The term “on” that is used to designate that an element is on anotherelement or located on a different layer or a layer includes both a casein which an element is located directly on another element or a layerand a case in which an element is located on another element via anotherlayer or still another element. In the entire description of the presentdisclosure, the same drawing reference numerals are used for the sameelements across various figures.

Although the terms “first,” “second,” and so forth are used to describediverse constituent elements, such constituent elements are not limitedby the terms. The terms are used only to distinguish a constituentelement from other constituent elements. Accordingly, in the followingdescription, a first constituent element may be a second constituentelement.

Hereinafter, exemplary embodiments of the present disclosure aredescribed in detail with reference to the attached drawings.

FIG. 1 is a plan view of a liquid crystal display device according to anembodiment of the present disclosure. FIG. 2 is a plan view showing onlya part of the configuration of FIG. 1. FIG. 3 is a cross-sectional viewtaken along the line I-I′ of FIG. 1.

Referring to FIGS. 1 to 3, a liquid crystal display device 10 accordingto an embodiment of the present disclosure includes a first substrate500, a gate electrode GE disposed on the first substrate 500, asemiconductor pattern layer 700 disposed on the gate electrode GE, and asource electrode SE1 and a drain electrode DE disposed on thesemiconductor pattern layer 700 and facing each other. Here, the gateelectrode GE includes a reference plane RP and a protrusion P1 extendingfrom the reference plane (RP) in a horizontal direction.

The first substrate 500 may be made of a material having heat resistanceand transparency. For example, the first substrate 500 may be made oftransparent glass or plastic, but the present disclosure is not limitedthereto.

A gate wiring (GL, GE) may be disposed on the first substrate 500. Thegate wiring (GL, GE) may include a gate line GL receiving a drivingsignal, a gate electrode GE protruding from the gate line GL, and a gateend (not shown) disposed on at least one end of the gate line GL.

The gate line GL may extend in a first direction. The first directionmay be substantially identical to the X-axis direction of FIG. 1. Thegate electrode GE may constitute three terminals of a thin filmtransistor together with a source electrode SE1 and a drain electrodeDE, which are described later.

The gate wiring (GL, GE) may contain one or more of an aluminum(Al)-base metal including an aluminum alloy, a silver (Ag)-based metalincluding a silver alloy, a copper (Cu)-based metal including a copperalloy, a molybdenum (Mo)-based metal including a molybdenum alloy,chromium (Cr), titanium (Ti), and tantalum (Ta). However, these metaland alloys are illustrative, and the material of the gate wiring (GL,GE) is not limited thereto. Any metal or polymer capable of being usedfor realizing a desired display device may be used as the material ofthe gate wiring (GL, GE).

The gate wiring (GL, GE) may have a single layer structure but is notlimited thereto. The gate wiring (GL, GE) may have a double layerstructure, a triple layer structure, or other multi-layer structures.

The gate electrode GE of the liquid crystal display according to anembodiment of the present disclosure may include a reference plane RPand a protrusion P1 extending from the reference plane RP.

The reference plane RP, as shown in FIG. 1, may be a plane extendingfrom a side not overlapping the source electrode SE1 and the drainelectrode DE in the perimeter of the gate electrode GE in horizontal andvertical directions. In an exemplary embodiment, the reference plane RPmay include a lateral side of the gate electrode GE. However, when thelateral side of the gate electrode GE is inclined (refer to FIG. 3), thereference plane RP may be plane formed by extending a side notoverlapping the source electrode SE1 and the drain electrode DE in theoutermost edge of the gate electrode GE in horizontal and verticaldirections. For reference, in the specification, the vertical directionmay be the Z-axis direction of FIG. 3, and the horizontal direction maybe any one direction parallel to the XY plane of FIG. 1.

That is, it can be understood that the above-described first directionand a second direction described below are included in the horizontaldirection.

The protrusion P1 may protrude from the reference plane (RP). Theprotrusion P1 may protrude from the reference plane (RP) in thehorizontal direction. When the source electrode SE1 and the drainelectrode DE, as shown in FIG. 1, extend in the positive direction ofX-axis or the negative direction of X-axis, the protrusion P1 may extendin the positive direction of X-axis and/or the negative direction ofX-axis.

The protrusion may overlap the source electrode SE1 and the drainelectrode DE, which are described later. For the convenience ofexplanation, the following terms are used. The length of the protrusionP1 protruding from the reference plane RP, that is, the distance betweenthe reference plane RP and the end of the protrusion P1, is representedby a first length 11. In addition, the width of the protrusion P1, thatis, the width of the protrusion P1 in a direction parallel to theextension direction of the reference plane RP, is represented by a firstwidth w1.

The first width w1 of the protrusion P1 may be substantially equal tothe width of the source electrode SE1 or the drain electrode DE.However, the first width w1 of the protrusion P1 is not limited thereto,and may be greater than the width of the source electrode SE1 or thedrain electrode DE. When the first width w1 of the protrusion P1 may besubstantially equal to the width of the source electrode SE1 or thedrain electrode DE, due to the presence of the protrusion P1, it ispossible to prevent an aperture ratio from being reduced.

The first length 11 of the protrusion P1 overlapping the sourceelectrode SE1 may be shorter than the distance between the data line DLand the gate line GE in FIG. 1. The first length 11 of the protrusion P1overlapping the drain electrode DE may be shorter than the distancebetween the gate electrode GE and the drain electrode expansion part 150in FIG. 1.

That is, the end of the protrusion P1 overlapping the source electrodeSE1 may be disposed between the data line DL and the gate electrode GE,and the end of the protrusion P1 overlapping the drain electrode DE maybe disposed between the gate electrode GE and the drain electrodeexpansion portion 150.

Hereinafter, the gate electrode GE of the liquid crystal displayaccording to some embodiments of the present disclosure is described inmore detail with reference to FIG. 3.

The gate electrode GE may include a first sub gate electrode SG1disposed on the first substrate 500 and a second sub gate electrode SG2disposed on the first sub gate electrode SG1.

For example, the first sub gate electrode SG1 and the second sub gateelectrode SG2 may be made of materials different from each other.Specifically, the first sub gate electrode SG1 and the second sub gateelectrode SG2 may be made of materials different from each other suchthat they have etch rates different from each other with respect to thesame etchant.

The first sub gate electrode SG1 and the second sub gate electrode SG2may partially overlap each other. The width of the first sub gateelectrode SG1 may be greater than the width of the second sub gateelectrode SG2. Therefore, the first sub gate electrode SG1 may includean overlapping area A1 in which the first sub gate electrode SG1overlaps the second sub gate electrode SG2, and non-overlapping areas A2in which the first sub gate electrode SG1 does not overlap the secondsub gate electrode SG2. The non-overlapping areas A2 may be disposed atboth sides of the overlapping area A1. That is, the non-overlappingareas A2 may protrude from the lateral side of the second sub gateelectrode SG2 in the horizontal direction. In other words, theprotrusion P1 of the gate electrode GE may include the non-overlappingareas A2. That is, the protrusion P1 may be formed to be integrated withthe first sub gate electrode SG1. In other words, the protrusion P1 maybe made of substantially the same material as the first sub gateelectrode SG1.

In this case, the reference plane may be a virtual plane extending fromthe perimeter of the second sub gate electrode SG2 in the vertical andhorizontal directions.

The semiconductor pattern layer 700 may contain amorphous silicon orpolycrystalline silicon, but the present disclosure is not limitedthereto. The semiconductor pattern layer 700 may be made an oxidesemiconductor.

The semiconductor pattern layer 700 may have various shapes, such as anisland shape, linear shape, and the like. When the semiconductor patternlayer 700 has a linear shape, the semiconductor pattern layer 700 may bedisposed under the data line DL to extend to the upper portion of thegate electrode GE.

In exemplary embodiment, the semiconductor pattern layer 700 may bepatterned in an area excluding a channel in substantially the same shapeas a data wiring (DL, SE, DE, 150), which is described later. In otherwords, the semiconductor pattern layer 700 may be disposed to overlapthe data wiring (DL, SE, DE, 150) over the entire area excluding thechannel. The channel may be disposed between a source electrode SE and adrain electrode facing each other. The channel serves to electricallyconnect the source electrode SE and the drain electrode DE, and thespecific shape thereof is not particularly limited.

The semiconductor pattern layer 700 may be provided thereon with anohmic contact layer (not shown) doped with n-type impurities in a highconcentration. The ohmic contact layer may overlap the entiresemiconductor pattern layer 700 or a part of the semiconductor patternlayer 700. However, in an exemplary embodiment in which thesemiconductor pattern layer 700 contains an oxide semiconductor, theohmic contact layer may be omitted.

The data wiring (DL, SE, DE, 150) may be disposed on the semiconductorpattern layer 700. The data wiring (DL, SE, DE, 150) may include: a dataline DL extending in the second direction, for example, in the Y-axisdirection of FIG. 1, to intersect with a gate line GL; a sourceelectrode SE branched from the data line DL to extend to the upperportion of the semiconductor pattern layer 700; a drain electrode DEspaced apart from the source electrode SE and disposed on thesemiconductor pattern layer 700 to face the source electrode SE with agate electrode GE or a channel as a center; and a drain electrodeexpansion part 150 extending from the drain electrode DE to beelectrically connected with a pixel electrode PE. Since the drainelectrode expansion part 150 has a larger width than the drain electrodeDE, it can be more easily electrically connected with the pixelelectrode PE.

The data wiring (DL, SE, DE, 150) may have a single layer structure ormulti-layer structure made of nickel (Ni), cobalt (Co), titanium (Ti),silver (Ag), copper (Cu), molybdenum (Mo), aluminum (Al), beryllium(Be), niobium (Nb), gold (Au), iron (Fe), selenium (Se), or tantalum(Ta). Further, the single layer structure or multi-layer structure mayalso be made of an alloy of the above metal and one or more elementsselected from the group consisting of titanium (Ti), zirconium (Zr),tungsten (W), tantalum (Ta), niobium (Nb), platinum (Pt), hafnium (Hf),oxygen (O), and nitrogen (N). However, the above materials areillustrative, and the material of the data wiring (DL, SE, DE, 150) isnot limited thereto.

FIG. 1 illustrates a case in which one thin film transistor is disposedin one pixel, but the scope of the present disclosure is not limitedthereto. That is, in another exemplary embodiment, a plurality of thinfilm transistors may be disposed in one pixel.

A passivation layer 600 may be disposed on the data wiring (DL, SE, DE,150) and the semiconductor pattern layer 700. The passivation layer 600may contain an inorganic insulating material. For example, thepassivation layer 600 may be made of silicon oxide, silicon nitride,silicon oxynitride, aluminum oxynitride, titanium oxynitride, zirconiumoxynitride, hafnium oxynitride, tantalum oxynitride, or tungstenoxynitride. However, the above materials are illustrative, and thematerial of the passivation layer is not limited thereto.

A contact hole for exposing a drain electrode expansion part 150 may beformed in the passivation layer 600.

A pixel electrode PE may be disposed on the passivation layer 600. Thepixel electrode PE may be electrically connected to the drain electrodeDE through the contact hole formed in the passivation layer 600.

In an exemplary embodiment, the pixel electrode PE may be made of atransparent conductor, such as indium tin oxide (ITO) or indium zincoxide (IZO), or a reflective conductor, such as aluminum.

FIG. 1 illustrates a case in which the pixel electrode PE has a flatshape, but the shape of the pixel electrode PE is not limited thereto.That is, in another exemplary embodiment, the pixel electrode may be astructure having one or more slits. Further, in still another exemplaryembodiment, one or more pixel electrodes may be disposed, and voltagesdifferent from each other may be applied to the plurality of pixelelectrodes.

As described above, when the gate electrode GE includes the protrusionP1, it is possible to prevent the light provided from a backlight unittoward the first substrate 500 from climbing the lateral side of thegate electrode to damage the semiconductor pattern layer 700. Thus, itis possible to prevent the characteristics of the semiconductor patternlayer 700 from being deteriorated by the light provided from thebacklight unit, and to suppress the occurrence of leakage of a thin filmtransistor.

Hereinafter, a liquid crystal display device according to anotherembodiment of the present disclosure is described. In the followingembodiment, the same reference numerals refer to the same or like partsfor the same configuration as the above-described configuration, andduplicate description thereof is omitted or simplified.

FIG. 4 is a cross-sectional view of a liquid crystal display deviceaccording to an embodiment of the present disclosure.

Referring to FIG. 4, a liquid crystal display device according to anembodiment of the present disclosure is different from the liquidcrystal display device shown in FIG. 3 in that this liquid crystaldisplay device includes a first sub gate electrode SG1, a second subgate electrode SG2, and a third sub gate electrode SG3.

The gate electrode GE may have a triple layer structure. Specifically,the gate electrode GE may include a first sub gate electrode SG1disposed on the first substrate 500, a second sub gate electrode SG2disposed on the first sub gate electrode SG1, and a third sub gateelectrode SG3 disposed on the second sub gate electrode SG2.

As described above, the first sub gate electrode SG1, the second subgate electrode SG2, and the third sub gate electrode SG3 may be made ofone or more of an aluminum (Al)-base metal including an aluminum alloy,a silver (Ag)-based metal including a silver alloy, a copper (Cu)-basedmetal including a copper alloy, a molybdenum (Mo)-based metal includinga molybdenum alloy, chromium (Cr), titanium (Ti), and tantalum (Ta).However the first sub gate electrode SG1, the second sub gate electrodeSG2, and the third sub gate electrode SG3 may be made of materialsdifferent form one another. However, in another exemplary embodiment,the third sub gate electrode SG3 and the second sub gate electrode SG2may be made of materials different from each other, and the third subgate electrode SG3 and the first sub gate electrode SG1 may be made ofmaterials the same as each other.

The first sub gate electrode SG1, the second sub gate electrode SG2, andthe third sub gate electrode SG3 may at least partially overlap oneanother. However, the width of the first sub gate electrode SG1 and thewidth of the second sub gate electrode SG2 may be greater than the widthof the third sub gate electrode SG3. Further, the width of the first subgate electrode SG1 may be substantially equal to the width of the secondsub gate electrode SG2.

In this case, the first sub gate electrode SG1 and the second sub gateelectrode SG2 may include an overlapping area A1 in which the first subgate electrode SG1 and the second sub gate electrode SG2 overlap thethird sub gate electrode SG3, and non-overlapping areas A2 in which thefirst sub gate electrode SG1 and the second sub gate electrode SG2 donot overlap the third sub gate electrode SG3. The non-overlapping areasA2 may be disposed at both sides of the overlapping area A1. That is,the non-overlapping areas A2 may protrude from the lateral side of thethird sub gate electrode SG3 in the horizontal direction. In otherwords, the protrusion P2 of the gate electrode GE may include thenon-overlapping areas A2 of the first sub gate electrode SG1 and thesecond sub gate electrode SG2. That is, the protrusion P2 may have adouble layer structure, and may be formed to be integrated with thefirst sub gate electrode SG1 and the second sub gate electrode SG2. Inother words, the protrusion P2 may be made of substantially the samematerial as the first sub gate electrode SG1 and the second sub gateelectrode SG2.

In this case, the reference plane may be a virtual plane extending fromthe perimeter of the third sub gate electrode SG3 in the vertical andhorizontal directions.

FIG. 5 is a plan view of a liquid crystal display device according toanother embodiment of the present disclosure.

Referring to FIG. 5, a liquid crystal display device according toanother embodiment of the present disclosure is different from theliquid crystal display device shown in FIG. 1 in that this liquidcrystal display device includes a source electrode SE2 having a U-shape.

The source electrode SE2 may include an electrode having a horseshoeshape, that is, a U shape. In this case, the drain electrode DE facingthe source electrode SE2 may be disposed in the inner space, that is,the U-shaped recess defined by the U-shaped source electrode SE2.

Specifically, the source electrode SE2 may extend from the data line DL,and the end thereof may have a U shape. That is, one end of the sourceelectrode SE2 may have a bar shape, and the other end thereof may have aU shape. The protrusion P1 may overlap the bar-shaped portion of thesource electrode SE2. That is, the U-shaped portion of the sourceelectrode SE2 may entirely overlap the gate electrode GE, and thebar-shaped portion thereof may partially overlap the gate electrode GE.In this case, the protrusion P1 may overlap the bar-shaped portion ofthe source electrode SE2, and the first width w1 of the protrusion P1may be substantially equal to the width of the bar-shaped portion of thesource electrode SE2.

FIG. 6 is a plan view of a liquid crystal display device according tostill another embodiment of the present disclosure. FIG. 7 is a planview showing only a part of the configuration of FIG. 6.

Referring to FIGS. 6 and 7, a liquid crystal display device according tostill another embodiment of the present disclosure is different from theliquid crystal display device shown in FIG. 1 in that this liquidcrystal display device includes a plurality of thin film transistors inon pixel.

As described above, a plurality of thin film transistors are disposed inone pixel.

FIGS. 6 and 7 illustrate a case that three thin film transistors aredisposed in one pixel.

Explaining this, the liquid crystal display device according to stillanother embodiment of the present disclosure includes a first drainelectrode DE_a extending from a data line DL. The first drain electrodeDE_a may include a bar-shaped portion and a U-shaped portion disposed atthe end of the bar-shaped portion.

A first source electrode SE_a may be disposed so as to correspond to thefirst drain electrode DE_a. The first source electrode SE_a may bedisposed in the recessed space of the U-shaped portion. In other words,the first drain electrode DE_a may surround at least a part of the firstsource electrode SE_a.

A second drain electrode DE_b may be disposed adjacent to the firstdrain electrode DE_a. The second drain electrode DE_b may be formed tobe integrated with the first drain electrode DE_a. Further, the seconddrain electrode DE_b may include a U-shaped portion.

A second source electrode SE_b may be disposed to face the second drainelectrode DE_b. The second drain electrode DE_b may surround at least apart of the second source electrode SE_b. The second source electrodeSE_b may have a bar shape and may extend. A third source electrode SE_cmay be disposed adjacent the second source electrode SE_b.

The third source electrode SE_c may be formed to be integrated with thesecond source electrode SE_b. The third source electrode SE_c may have abar shape extending in a longitudinal direction. A third drain electrodeDE_c may be disposed to face the third source electrode SE_c. The thirddrain electrode DE_c may have a bar shape extending in a longitudinaldirection.

The third source electrode SE_c and the third drain electrode DE_c mayface each other in a horizontal direction. That is, a part of thelateral side of the third source electrode SE_c and a part of thelateral side of the third drain electrode DE_c may face each other.

The reference plane RP may be a plane formed by extending a side notoverlapping the source electrode and the drain electrode in theperimeter of the gate electrode GE1 in horizontal and verticaldirections. As described in the liquid crystal display devices accordingto some embodiments of the present disclosure, the following protrusionsmay protrude from the reference plane RP at predetermined distances.

In this case, the liquid crystal display device according to stillanother embodiment of the present disclosure may include first to fifthprotrusions Pa to Pe.

The first protrusion Pa may be disposed to overlap the bar-shapedportion of the first source electrode SE_a. The second protrusion Pb maybe disposed to overlap the bar-shaped portion of the first drainelectrode DE_a. The third protrusion Pc may be disposed to overlap thebar-shaped portion of the second source electrode SE_b. The fourthprotrusion Pd may be disposed to overlap the bar-shaped portion of thethird drain electrode DE_c. The fifth protrusion Pe may be disposed tooverlap the bar-shaped portion of the third source electrode SE_c.

As described above, in an exemplary embodiment, the gate electrode GEmay include the first sub gate electrode SG1 and the second sub gateelectrode SG2. In this case, the first to fifth protrusions Pa to Pe maybe formed to be integrated with the first sub gate electrode SG1. Thatis, the first to fifth protrusions Pa to Pe may be made of substantiallythe same material as the first sub gate electrode SG1.

It is exemplified in the present embodiment that the liquid crystaldisplay device has five protrusions Pa to Pe. However, the number ofprotrusions is illustrative, and is not limited thereto. That is, inanother embodiment, some of the five protrusions may be omitted.Further, in another embodiment, the number of protrusions may exceedfive.

When the protrusions are disposed as above, it is possible to preventthe light provided from a backlight unit toward the first substrate 500from intruding into the semiconductor pattern layer 700 along thelateral side of the gate electrode GE to damage the semiconductorpattern layer 700.

FIG. 8 is a cross-sectional view of a liquid crystal display deviceaccording to still another embodiment of the present disclosure.

Referring to FIG. 8, a liquid crystal display device according to stillanother embodiment of the present disclosure may further include asecond substrate 1000 facing the first substrate 500.

Since the source electrode SE and the drain electrode DE may be disposedon the first substrate 500 as described with reference to FIG. 3, adetailed description thereof is omitted.

A passivation layer 600 may be disposed on the data wiring (DL, SE, DE,150) and the semiconductor pattern layer 700. The passivation layer 600may contain an inorganic insulating material. For example, thepassivation layer 600 may be made of silicon oxide, silicon nitride,silicon oxynitride, aluminum oxynitride, titanium oxynitride, zirconiumoxynitride, hafnium oxynitride, tantalum oxynitride, or tungstenoxynitride. However, the above materials are illustrative, and thematerial of the passivation layer is not limited thereto.

A contact hole for exposing a drain electrode expansion part 150 may beformed in the passivation layer 600.

A pixel electrode PE may be disposed on the passivation layer 600. Thepixel electrode PE may be electrically connected to the drain electrodeDE through the contact hole formed in the passivation layer 600.

In an exemplary embodiment, the pixel electrode PE may be made of atransparent conductor, such as indium tin oxide (ITO) or indium zincoxide (IZO), or a reflective conductor, such as aluminum.

The second substrate 1000 may be made of a material having heatresistance and transparency. For example, the second substrate 1000 maybe made of transparent glass or plastic, but the present disclosure isnot limited thereto.

A black matrix BM1, as a light blocking member for preventing lightleakage and light interference between adjacent pixel areas, may bedisposed on the second substrate 1000. Further, a color filter CF1 ofred, blue, and green may be disposed for each unit pixel.

An overcoat layer OC made of an organic material may be disposed on theblack matrix BM1 and the color filter CF1. In the present embodiment,since the overcoat layer OC may be commonly known overcoat layers OC orobvious combinations thereof, a detail description thereof is omitted.

A common electrode CE may be disposed on the overcoat layer OC. Thecommon electrode CE may be a front electrode, and may be made of atransparent conductor, such as indium tin oxide (ITO) or indium zincoxide (IZO), or a reflective conductor, such as aluminum.

FIG. 9 is a cross-sectional view of a liquid crystal display deviceaccording to still another embodiment of the present disclosure.

Referring to FIG. 9, a liquid crystal display device according to stillanother embodiment of the present disclosure is different from theliquid crystal display device shown in FIG. 9 in that a black matrix BM2and a color filter CF2 are disposed over the substrate 500.

Since the source electrode SE and the drain electrode DE may be disposedon the first substrate 500 as described with reference to FIG. 3, adetailed description thereof is omitted.

A passivation layer 600 may be disposed on the data wiring (DL, SE, DE,150) and the semiconductor pattern layer 700. The passivation layer 600may contain an inorganic insulating material. For example, thepassivation layer 600 may be made of silicon oxide, silicon nitride,silicon oxynitride, aluminum oxynitride, titanium oxynitride, zirconiumoxynitride, hafnium oxynitride, tantalum oxynitride, or tungstenoxynitride. However, the above materials are illustrative, and thematerial of the passivation layer is not limited thereto.

A contact hole for exposing a drain electrode expansion part 150 may beformed in the passivation layer 600.

A color filter CF2 may be formed on the passivation layer 600. The colorfilter CF2 may include one or more selected from a blue color filter, agreen color filter, and a red color filter. In an exemplary embodiment,the heights of the blue color filter, the green color filter, and thered color filter may be different from one another.

A contact hole for exposing the drain electrode DE may be disposed inthe color filter CF2. The contract hole disposed in the color filter CF2may overlap the above-mentioned contact hole formed in the passivationlayer 600. Thus, the drain electrode DE is exposed, and a pixelelectrode PE, which is described later, may be electrically connectedwith the exposed drain electrode DE.

A pixel electrode PE may be disposed on the color filter CF2. The pixelelectrode PE may be electrically connected with the drain electrode DEthrough the contact hole formed in the passivation layer 600 and thecontact hole formed in the color filter CF2.

In an exemplary embodiment, the pixel electrode may be made of atransparent conductor, such as indium tin oxide (ITO) or indium zincoxide (IZO), or a reflective conductor, such as aluminum.

A black matrix BM2 may be disposed on the passivation layer 600. Theblack matrix BM2 may be disposed to extend along the data line DL. Thewidth of the black matrix BM2 may be substantially equal to or greaterthan the width of the data line DL. Further, the black matrix BM2 maycover the source electrode SE, the drain electrode DE, and the channel.In other words, the black matrix BM2 may overlap a thin film transistor,and may cover the area in which the thin film transistor.

The black matrix BM2 serves to block external incident light. For thispurpose, the black matrix BM2 may be made of a photosensitive resincontaining a black pigment. However, this photosensitive resin isillustrative, and the material of the black matrix BM2 is not limitedthereto. Any material may be used as the material of the black matrixBM2 as long as it has physical properties suitable for blocking externalincident light.

The second substrate 1000 may be disposed to face the first substrate500. A common electrode CE, as a front electrode, may be disposed on thesecond substrate 1000. Since this common electrode CE is substantiallyidentical to that described with reference to FIG. 8, a detaileddescription thereof is omitted.

FIGS. 8 and 9 illustrate a case in which the common electrode CE isdisposed on the second substrate 1000, but the scope of the presentdisclosure is not limited thereto. That is, in another exemplaryembodiment, the common electrode CE may also be disposed on the firstsubstrate 500. That is, in another exemplary embodiment, the liquidcrystal display device may be a liquid crystal display device of a PLSor IPS mode.

Hereinafter, a method of manufacturing a liquid crystal display deviceaccording to an embodiment of the present disclosure is described. Someof the configurations described below may be the same as those of theabove-mentioned liquid crystal display according to some embodiments ofthe present disclosure. In order to avoid duplicate description, adescription of some configurations is omitted.

FIGS. 10 to 15 are cross-sectional views illustrating a method ofmanufacturing a liquid crystal display device according to an embodimentof the present disclosure.

Referring to FIGS. 10 to 15, a method of manufacturing a liquid crystaldisplay device according to an embodiment of the present disclosureincludes the steps of: providing a first substrate including a firstconductive film 250 and a second conductive film 350 disposed on thefirst conductive film 250; forming a first photoresist pattern PR1 onthe second conductive film 350; and forming a gate electrode GEincluding a first sub gate electrode SG1 and a second sub gate electrodeSG2 using the first photoresist pattern PR1 as an etching mask.

First, a first conductive film 250 is formed on a first substrate 500.The first conductive film 250 may be made of a material substantiallyidentical to the metal material constituting the above-mentioned gateelectrode GE. The first conductive film 250 may be formed by chemicalvapor deposition or sputtering.

A second conductive film 350 may be formed on the first conductive film250. The second conductive film 350 may be made of a materialsubstantially identical to the metal material constituting theabove-mentioned gate electrode GE. The second conductive film 350 may beformed by chemical vapor deposition or sputtering. However, the firstconductive film 250 and the second conductive film 350 may be made ofmaterials different from each other. That is, the first conductive film250 and the second conductive film 350 may be made of materials havingetch rates different from each other with respect to the same etchant.This is related to a method of forming protrusions using the differencein etch rate therebetween, which is described later.

Subsequently, a first photoresist pattern PR1 is formed on the secondconductive 350. The first photoresist pattern PR1 may be obtained byapplying a photoresist film and then exposing and developing the appliedphotoresist film.

Subsequently, referring to FIG. 11, the first conductive film 250 andthe second conductive film 350 are etched by using the first photoresistpattern PR1 as an etching mask to form a gate electrode GE. As describedabove, the gate electrode GE may include a first sub gate electrode SG1and a second sub gate electrode SG2.

The step of forming the gate electrode GE by etching the firstconductive film 250 and the second conductive film 350 may include thestep of forming the first sub gate electrode SG1 and the second sub gateelectrode SG2 by etching the first conductive film 250 and the secondconductive film 350. That is, the first conductive film 250 and thesecond conductive film 350 may be isotropically etched through a wetetching process.

Subsequently, referring to FIG. 12, the formed first sub gate electrodeSG1 and second sub gate electrode SG2 are over-etched to form aprotrusion P1. As described above, the etch rates of the first sub gateelectrode SG1 and second sub gate electrode SG2 with respect to thespecific etchant may be different from each other. Specifically, withrespect to the etchant used in the method of manufacturing a liquidcrystal display device according to an embodiment of the presentdisclosure, the etch rate of the first sub gate electrode SG1 may belower than the etch rate of the second sub gate electrode SG2. In thiscase, when the first sub gate electrode SG1 and second sub gateelectrode SG2 are exposed to the etchant as shown in FIG. 12, a skewphenomenon occurs at both sides of the second sub gate electrode SG2formed beneath the first photoresist pattern PR1, and thus the end ofthe first sub-gate electrode SG1 may protrude compared to the end of thesecond sub-gate electrode SG2. That is, the protrusion P1 of the gateelectrode GE may be formed as the first sub gate electrode SG1.

Since the first sub gate electrode SG1 and the second sub gate electrodeSG2 may be substantially identical to those described with reference toFIG. 3, a detailed description thereof is omitted.

Subsequently, referring to FIG. 13, a gate insulating film 200 may bedisposed on the gate electrode GE. The gate insulating film 200 may beformed by chemical vapor deposition or the like.

Subsequently, referring to FIG. 14, a semiconductor pattern layer 700, asource electrode SE, and a drain electrode DE may be disposed on thegate insulating film 200.

Subsequently, a passivation layer 600 may be disposed on the sourceelectrode SE, the drain electrode DE, and the semiconductor patternlayer 700.

Subsequently, a pixel electrode PE may be disposed on the passivationlayer 600. The source electrode SE, the drain electrode DE, and thesemiconductor pattern layer 700 may be substantially identical to thosedescribed in the liquid crystal display devices according to someembodiments of the present disclosure. Therefore, a detailed descriptionthereof is omitted.

Subsequently, referring to FIG. 15, a second substrate 1000 providedwith a black matrix BM, a color filer CF, an overcoat OC, and a commonelectrode CE is attached to the first substrate 500 such that secondsubstrate 1000 and the first substrate 500 face each other. The blackmatrix BM, the color filer CF, the overcoat OC, and the common electrodeCE may be substantially identical to those described in the liquidcrystal display devices according to some embodiments of the presentdisclosure. Therefore, a detailed description thereof is omitted.

As described above, according to embodiments of the present disclosure,the following effects may be achieved.

In the liquid crystal display, it is possible to prevent thecharacteristics of a semiconductor pattern from being deteriorated bythe light provided from a backlight unit.

In the crystal display, it is possible to prevent the leakage of asemiconductor pattern from occurring by the light provided from thebacklight unit.

The effects of the present disclosure are not limited by the foregoing,and other various effects are anticipated herein.

Although the preferred embodiments of the present disclosure have beendisclosed for illustrative purposes, those skilled in the art wouldappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of theaccompanying claims. That is, the exemplary embodiments should beconsidered in a descriptive sense only and not for purposes oflimitation.

What is claimed is:
 1. A liquid crystal display device, comprising: afirst substrate; a gate electrode disposed on the first substrate; asemiconductor pattern layer disposed on the gate electrode; and a sourceelectrode and a drain electrode disposed on the semiconductor patternlayer and facing each other, wherein the gate electrode includes areference plane and a protrusion protruding from the reference plane ina horizontal direction, and the protrusion overlaps the source electrodeand the drain electrode, and wherein the protrusion includes a pluralityof protrusions disposed to correspond to the source electrode and thedrain electrode.
 2. The liquid crystal display device of claim 1,wherein the gate electrode includes a first sub gate electrode and asecond sub gate electrode disposed on the first sub gate electrode, thefirst sub gate electrode includes an overlapping area in which the firstsub gate electrode overlaps the second sub gate electrode, andnon-overlapping areas in which the first sub gate electrode does notoverlap the second sub gate electrode, and the protrusion includes thenon-overlapping areas.
 3. The liquid crystal display device of claim 2,wherein the first sub gate electrode and the second sub gate electrodeare made of materials different from each other.
 4. The liquid crystaldisplay device of claim 1, wherein the gate electrode comprises: a firstsub gate electrode; a second sub gate electrode disposed on the firstsub gate electrode; and a third sub gate electrode disposed on thesecond sub gate electrode, wherein the first sub gate electrode and thesecond sub gate electrode include an overlapping area in which the firstsub gate electrode and the second sub gate electrode overlap the thirdsub gate electrode, and non-overlapping areas in which the first subgate electrode and the second sub gate electrode do not overlap thethird sub gate electrode, and the protrusion includes thenon-overlapping areas of the first sub gate electrode and the second subgate electrode.
 5. The liquid crystal display device of claim 4, whereinthe third sub gate electrode and the second sub gate electrode are madeof materials different from each other.
 6. The liquid crystal displaydevice of claim 5, wherein the third sub gate electrode and the firstsub gate electrode are made of materials the same as each other.
 7. Theliquid crystal display device of claim 1, wherein the width of theprotrusion is equal to the width of the source electrode or the drainelectrode overlapping the protrusion.
 8. The liquid crystal displaydevice of claim 1, wherein the source electrode includes a bar-shapedportion and a U-shaped portion, and the protrusion overlaps thebar-shaped portion of the source electrode.
 9. The liquid crystaldisplay device of claim 1, wherein the source electrode includes firstto third source electrodes, the drain electrode includes first to thirddrain electrodes corresponding to the first to third source electrodes,and the protrusion includes first to fifth protrusions, wherein thefirst to fifth protrusions respectively overlap the first to thirdsource electrodes and the first to third drain electrodes.
 10. Theliquid crystal display device of claim 1, further comprising: a secondsubstrate facing the first substrate; and a common electrode disposed onthe second substrate.
 11. A method of manufacturing a liquid crystaldisplay device, comprising: providing a first substrate including afirst conductive film and a second conductive film disposed on the firstconductive film; forming a first photoresist pattern on the secondconductive film; and forming a gate electrode including a first sub gateelectrode and a second sub gate electrode by etching the firstconductive film and the second conductive film using the firstphotoresist pattern as an etching mask, wherein the gate electrodeincludes a reference plane and a protrusion protruding from thereference plane in a horizontal direction.
 12. The method of claim 11,wherein the first conductive film and the second conductive film aremade of materials having etch rates different from each other withrespect to a predetermined etchant.
 13. The method of claim 12, whereinthe forming the gate electrode including the first sub gate electrodeand the second sub gate electrode by etching the first conductive filmand the second conductive film using the first photoresist pattern as anetching mask includes: wet-etching the first conductive film and thesecond conductive film.
 14. The method of claim 11, wherein the formingthe gate electrode including the first sub gate electrode and the secondsub gate electrode by etching the first conductive film and the secondconductive film using the first photoresist pattern as an etching maskincludes: over-etching the second sub gate electrode to form theprotrusion as a part of the first sub gate electrode after forming thefirst sub gate electrode and the second sub gate electrode by etchingthe first conductive film and the second conductive film.